Generally described, known single and multiple dose Dry Powder Inhalers (DPIs) are an established alternative to pressurized metered dose inhalers (pMDIs). DPIs can use: (a) individual pre-measured doses in blisters containing the drug, which can be inserted into the device prior to dispensing; or (b) bulk powder reservoirs which are configured to administer successive quantities of the drug to the patient via a dispensing chamber which dispenses the proper dose. See generally Prime et al., Review of Dry Powder Inhalers, 26 Adv. Drug Delivery Rev., pp. 51-58 (1997); and Hickey et al., A new millennium for inhaler technology, 21 Pharm. Tech., n. 6, pp. 116-125 (1997).
In operation, DPI devices strive to administer a uniform aerosol dispersion amount in a desired physical form of the dry powder (such as a particulate size or sizes) into a patient's airway and direct it to a desired internal deposit site(s).
Unfortunately, some dry powder inhalers can retain some amount of the drug within the device that may be delivered with another dose of the drug. This may be particularly prone to happen when a user actuates the inhaler but does not inhale the indexed dose of medicament.
There remains a need for alternative inhalers and/or dose containment devices that can be used to deliver medicaments.